On Fri, Feb 24, 2017 at 08:44:00PM -0300, Marcelo Cerri wrote:
>
> This is probably caused by the way that the xts template is handling the
> underline algorithm selection.
Good catch. I think the bigger issue here is that when requesting
for an XTS that doesn't need a fallback we shouldn't be using an
underlying ECB that needs one. So this patch should fix the hang.
Thanks,
---8<---
Subject: crypto: xts - Propagate NEED_FALLBACK bit
When we're used as a fallback algorithm, we should propagate
the NEED_FALLBACK bit when searching for the underlying ECB mode.
This just happens to fix a hang too because otherwise the search
may end up loading the same module that triggered this XTS creation.
Fixes: f1c131b45410 ("crypto: xts - Convert to skcipher")
Reported-by: Harald Freudenberger <fre...@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herb...@gondor.apana.org.au>
diff --git a/crypto/xts.c b/crypto/xts.c
index 410a2e2..2066161 100644
--- a/crypto/xts.c
+++ b/crypto/xts.c
@@ -463,6 +463,7 @@ static int create(struct crypto_template *tmpl, struct
rtattr **tb)
struct xts_instance_ctx *ctx;
struct skcipher_alg *alg;
const char *cipher_name;
+ u32 mask;
int err;
algt = crypto_get_attr_type(tb);
@@ -483,18 +484,19 @@ static int create(struct crypto_template *tmpl, struct
rtattr **tb)
ctx = skcipher_instance_ctx(inst);
crypto_set_skcipher_spawn(&ctx->spawn, skcipher_crypto_instance(inst));
- err = crypto_grab_skcipher(&ctx->spawn, cipher_name, 0,
- crypto_requires_sync(algt->type,
- algt->mask));
+
+ mask = crypto_requires_sync(algt->type, algt->mask) |
+ ((algt->type ^ CRYPTO_ALG_NEED_FALLBACK) & algt->mask &
+ CRYPTO_ALG_NEED_FALLBACK);
+
+ err = crypto_grab_skcipher(&ctx->spawn, cipher_name, 0, mask);
if (err == -ENOENT) {
err = -ENAMETOOLONG;
if (snprintf(ctx->name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
cipher_name) >= CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
- err = crypto_grab_skcipher(&ctx->spawn, ctx->name, 0,
- crypto_requires_sync(algt->type,
- algt->mask));
+ err = crypto_grab_skcipher(&ctx->spawn, ctx->name, 0, mask);
}
if (err)
--
Email: Herbert Xu <herb...@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
